Field
Exemplary embodiments of the present invention relate to a hybrid door for an automobile in which the inside panel and outside panel are made of different types of materials; and, particularly, to a hybrid door for an automobile which can reduce the weight of the automobile while maintaining high strength and a dent-resistant property.
Description of Related Art
In the car manufacturing industry, weight of the chassis of an automobile continues to be reduced for reducing carbon dioxide included in emissions in accordance with environment regulations, improving fuel efficiency of fossil fuel vehicles, and reducing the battery consumption of electric vehicles.
FIG. 1 is an exploded perspective view of a known automobile door.
As illustrated in FIG. 1, in general, an automobile door basically includes an inside panel and an outside panel. The inside panel is chiefly formed of a 28K steel plate, and the outside panel is chiefly formed of a 35K steel plate.
Specific gravity of the steel plate is about 7.8 and is problematic in that the steel plate has shortcomings, such as a reduction of fuel efficiency in the automobile, because steel plate increases weight of the door.
In particular, in accordance with extreme carbon dioxide regulation policies, in the case of parts using thin steel plates, such as the door, the hood, and the trunk whose reduction of weight may be no longer expected, as known steel plates for automobiles having high strength, car manufacturers try to gradually adopt nonferrous-series light materials, such as aluminum, plastic, and magnesium, instead of the steel materials.
However, the nonferrous-series light materials are problematic in that they are expensive and require additional cost in order to improve welding and painting properties.
There has recently been proposed a method of manufacturing a thin steel plate using a high strength steel plate, such as dual phase (DP) steel having both machinability and strength, for example, 490DP or 590DP, and applying the thin steel plate to automobile parts in order to reduce the weight of automobile parts through designs resulting in reduced thickness.
The method of reducing the thickness of steel plate has a disadvantage in that reduction in thickness is limited because part strength is reduced if the thickness of the steel plate becomes too thin. As a result, reduction of weight in the automobile door using a high-strength thin steel plate is limited.
Accordingly, there is an urgent need to develop materials for reducing weight of the automobile door while retaining hardness and dent-resistance that are equal to or greater than those of conventional steel plates in order to improve fuel efficiency of an automobile and cope with enforced environment regulations.